Stone-free Outcomes of Flexible Ureteroscopy for Renal Calculi Utilizing Computed Tomography Imaging

Clinical efficacy and safety of flexible ureteroscopy and percutaneous nephrolithotomy for large kidney stones: A retrospective comparative study

BACKGROUND

Renal stones ranging 20-40 mm are very common in China. Although no large-sample clinical studies have confirmed the clinical efficacy and safety of this method, there is also a lack of comparative data with traditional treatment.

AIM

To investigate the clinical efficacy of flexible ureteroscopy (FURS) and percutaneous nephrolithotomy (PCNL) by postoperative stone clearance and changes in soluble vascular cell adhesion molecule 1 (sVCAM-1) and kidney injury molecule 1 (KIM-1) levels in patients with large kidney stones (> 2 cm in diameter).

METHODS

This single-center observational study was performed at a Chinese hospital between January 1, 2021, and October 30, 2023. All 250 enrolled patients were diagnosed with large kidney stones (> 2 cm) and divided into a FURS group (n = 145) and a PCNL group (n = 105) by the surgical method. The FURS group was treated with flexible ureteroscopy and the PCNL group was treated with percutaneous nephrolithotomy. The operation time, time to palinesthesia, intraoperative blood loss, drop in hemoglobin, length of hospital stay, stone clearance rate, and complications were recorded in the two groups. Preoperative and postoperative serum sVCAM-1 levels, erythrocyte sedimentation rate (ESR), urine KIM-1 levels, preoperative and postoperative pain visual analog scale (VAS) and Wisconsin Stone Quality of Life Questionnaire (WISQOL) scores were also documented.

RESULTS

All 250 eligible patients completed the follow-up. There were no significant differences in baseline characteristics between the two groups (P > 0.05). The operation time in the FURS group was significantly greater than that in the PCNL group. The time to ambulation, intraoperative blood loss, decrease in hemoglobin, and length of hospital stay were significantly lower in the FURS group than in the PCNL group. The FURS group also had a significantly higher stone clearance rate and a lower incidence of postoperative complications. There was no significant difference in antibiotic use between the groups. Postoperative serum sVCAM-1 levels, urine KIM-1 levels, and VAS scores were lower in the FURS group than in the PCNL group, but postoperative ESR and WISQOL scores were greater in the FURS group than in the PCNL group.

CONCLUSION

FURS demonstrated superior clinical efficacy in treating large kidney stones (> 2 cm in diameter) compared PCNL. It not only improved the postoperative stone clearance rate and reduced complications and recovery time but also positively affected serum SCM-1, ESR, and urine KIM-1 levels, subsequent improvement of patient quality of life.

Optimizing outcome reporting after robotic flexible ureteroscopy for management of renal calculi: Introducing the concept of tetrafecta

Robotic flexible ureteroscopy (RFURS) has shown encouraging results in terms of stone free rate (SFR) and better ergonomics compared to conventional FURS. However, few studies have reported its outcomes. The goal of this study was to report our initial results of RFURS, furthermore we proposed a novel metrics for composite outcome reporting named tetrafecta. A retrospective analysis of electronic records of 100 patients treated with RFURS for renal stones between 2019 till 2023 was performed. Tetrafecta criteria included, complete stone removal after a single treatment session, without auxiliary procedures, absence of high-grade complications (GIII-V) and same-day hospital discharge. Mean patient age and stone size were 40.7 ± 9.2 and 11.7 ± 5.8 mm, respectively. Median stone volume was 916 (421-12,235) mm3. Twenty-eight patients had multiple renal stones. Staghorn stones were seen in 12 patients. Preoperative DJ stent was fixed in 58 patients. Median operative time and stone treatment time were 116 min (97-148) and 37 (22-69) min. The median stone treatment efficiency (STE) was 21.6 (8.9-41.6). A strong positive correlation between stone volume and STE (R = 0.8, p < 0.0001). Overall, 73 patients were stone free after the initial treatment session while tetrafecta was achieved in 70 patients. Univariate analysis showed that the stone size (p = 0.008), acute infundibulopelvic angle (p = 0.023) and preoperative stenting (p = 0.017) had significant influence on achieving tetrafecta. Multivariate analysis identified preoperative stenting (OR 0.3, 95% CI 0.1-0.8, p = 0.019) as the only independent predictor of tetrafecta achievement. A comprehensive reporting methodology for reporting outcomes of RFURS is indicated for patient counseling and comparing different techniques. Tetrafecta was achieved in 70% of cases. Presence of significant residual stones ≥ 3mm was the leading cause of missing tetrafecta. Absence of preoperative stent was the only predictor of missing tetrafecta.

Does preoperative silodosin administration facilitate ureteral dilatation during flexible ureterorenoscopy? A randomized clinical trial

PURPOSE

To assess whether preoperative administration of silodosin can facilitate the placement of ureteral access sheath (UAS) prior to flexible ureteroscopy (F-URS) and reduce the occurrence of ureteric injury in challenging cases.

METHODS

This prospective randomized clinical trial was carried out on 147 patients diagnosed with upper ureteric stone or stone kidney, non-stented. The patients were randomly divided into two equal groups. Group A (silodosin group) included patients in whom F-URS was done with daily preoperative intake of 8 mg silodosin for 1 week and group B (placebo/control group) included patients in whom F-URS was done with daily preoperative intake of placebo tablets.

RESULTS

In group A, a total of 23 (33.3%) experienced ureteral wall injury following UAS insertion, while in group B, this occurred in 40 patients (59.7%). There was a statistically significant difference in the grade of ureteral wall injury between the two groups (P < 0.001). In the multiple regression analysis, age, operative time and silodosin were found to be significant risk factors for ureteral wall injury (P = 0.007, 0.041 and < 0.001, respectively).

CONCLUSIONS

The administration of silodosin prior to retrograde intrarenal surgery (RIRS) effectively prevented significant ureteral wall damage and reduced initial postoperative discomfort.

Spectral characterization of renal calculi collected from population in downtown Madrid (Spain)

This paper reports on a comprehensive approach to characterize a set of kidney stones through various analytical techniques including ESEM-EDS, XRD, Raman, and CL spectroscopy, linked to an assessment of the patient's lifestyle and dietary habits. The use of these techniques can provide valuable insights into the underlying causes of stone formation and guide strategies for prevention and treatment. ESEM-EDS and XRD are commonly used techniques for kidney stone characterization due to their complementary nature, enabling the identification of a wide range of renal calculi. However, these techniques may not be sensitive enough to determine the detailed composition of the samples. In such cases, Raman and CL techniques can be used to provide more precise information about the chemical and structural composition of the stones. Raman spectroscopy, for example, can identify molecular phases observed under an optical microscope characterizing chemical compositions through vibrational modes associated with specific bonds. The CL spectral emission within the 250-850 nm range can also yield valuable information about the mineral phases, including the identification of structural crystallinity, hydrated molecules, Ca-OH bonds, and oxygen defects. By correlating spectral analyses with patient habits, this study identifies potential exogenous factors contributing to stone formation, including excess protein consumption, urinary bacterial infections, and oxalate-rich diets. This comprehensive approach provides a more complete understanding of the composition of kidney stones helping to personalized prevention and treatment strategies.

Ureterorenoscopic stone procedures have low success rates and poor post-operative follow-up: results from an Australian tertiary health service

BACKGROUND

To assess the results of ureterorenoscopy (URS) for upper tract urolithiasis in a contemporary Australian tertiary healthcare setting.

METHODS

Hospital records of all URS stone procedures performed between January 2017 and December 2018 in a metropolitan service were retrospectively reviewed. Outcome measures including stone free rates, adherence to postoperative follow-up and complications rates were recorded.

RESULTS

385 patients (387 renal units) with mean age 53.8 (range 18-89) underwent URS for stones measuring between 2 and 27 mm (median 8 mm). 465 URS were performed with 1029 total procedures performed. 48.6% of operations were performed as day cases. Complications were recorded in 9% of the 465 URS cases with 42.9% of these Clavien II or more. The representation rate to our Emergency Departments was 15.4%. Only 49.1% (201) of patients had a follow-up review with imaging to assess stone free rates. Of the 201 patients who underwent imaging, only 38.3% were stone free. Stone analysis was performed in 34.5%.

CONCLUSION

Less than half of all patients were reviewed despite undergoing expensive, time consuming surgery for a condition with a high recurrence rate. In agreement with recent publications stone-free rates were low, with significant complications and representation rates. Stone surgery should be given the attention and resources equivalent to cancer surgery to improve results.

LEVEL OF EVIDENCE

2b.

Real-world Practice Stone-free Rates After Ureteroscopy: Variation and Outcomes in a Surgical Collaborative

BACKGROUND

Studies assessing the stone-free rate (SFR) after ureteroscopy are limited to expert centers with varied definitions of stone free. Real-world data including community practices related to surgeon characteristics and outcomes are lacking.

OBJECTIVE

To evaluate the SFR for ureteroscopy and its predictors across diverse surgeons in Michigan.

DESIGN, SETTING, AND PARTICIPANTS

We assessed the Michigan Urological Surgery Improvement Collaborative (MUSIC) clinical registry for patients with renal or ureteral stones treated with ureteroscopy between 2016 and 2021 who had postoperative imaging.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Stone free was defined as no fragments on imaging reports within 60 d entered by independent data abstractors. Factors associated with being stone free were examined using logistic regression, including annual surgeon volume. We then assessed variation in surgeon-level SFRs adjusted for risk factors.

RESULTS AND LIMITATIONS

We identified 6487 ureteroscopies from 164 surgeons who treated 2091 (32.2%) renal and 4396 (67.8%) ureteral stones. The overall SFRs were 49.6% (renal) and 72.7% (ureteral). Increasing stone size, lower pole, proximal ureteral location, and multiplicity were associated with not being stone free. Female gender, positive urine culture, use of ureteral access sheath, and postoperative stenting were associated with residual fragments when treating ureteral stones. Adjusted surgeon-level SFRs varied for renal (26.1-72.4%; p < 0.001) and ureteral stones (52.2-90.2%; p < 0.001). Surgeon volume was not a predictor of being stone free for renal stones. Limitations include the lack of imaging in all patients and use of different imaging modalities.

CONCLUSIONS

The real-world complete SFR after ureteroscopy is suboptimal with substantial surgeon-level variation. Interventions focused on surgical technique refinement are needed to improve outcomes for patients undergoing ureteroscopy and stone intervention.

PATIENT SUMMARY

Results from a diverse group of community practicing and academic center urologists show that for a large number of patients, it is not possible to be completely stone free after ureteroscopy. There is substantial variation in surgeon outcomes. Quality improvement efforts are needed to address this.

Enhanced popcorning using polyanionic chelating solutions as irrigation

Poly-anionic compounds can chelate divalent cations and dissolve calcium oxalate stone. Our objective was to assess how much concurrent irrigation with poly-anionic chelating solutions during non-contact laser lithotripsy or popcorning could improve stone ablation rate. A popcorning model was created by lowering a ureteroscope with thulium fiber laser into a test tube calyx. Begostones of matching size and mass were placed in the test tube and treated with the laser while irrigating with different iso-osmolar poly-anionic solutions. We compared 0.9% sodium chloride (NaCl), sodium citrate, sodium hexa-metaphosphate, and sodium ethylenediaminetetraacetate (EDTA) solutions. After treatment, residual stones were passed through a 1 mm sieve, and remaining fragments greater than 1 mm were weighed as remaining stone mass. Average remaining stone mass after lithotripsy with NaCl irrigation was 27.8% (± 10.0%). The average remaining stone mass after lithotripsy with hexa-metaphosphate, sodium citrate, and EDTA irrigation was 28.9% (± 13.4%), 17.5% (± 10.5%), and 9.8% (± 5.7%) respectively. Compared with NaCl, there was a 37% reduction in remaining stone mass when using citrate (p = 0.008) and a 64.7% reduction when using EDTA irrigation during lithotripsy (p < 0.001). Concurrent irrigation with citrate or EDTA solutions synergistically enhances the efficacy laser lithotripsy in this in vitro popcorning model. This may lead to tangible improvements in endoscopic stone removal outcomes; however, the effectiveness on different stone types and safety during short duration lithotripsy should be further investigated.

Retrograde intrarenal surgery for lower pole stones utilizing stone displacement technique yields excellent results

Objective

To evaluate the long-term stone-free rate (SFR) of retrograde intra-renal surgery (RIRS) in the treatment of lower pole renal calculi using only basket relocation and identify independent predictors of stone-free status.

Methods

All consecutive patients undergoing RIRS lower pole renal calculi at a single high-volume tertiary center were analyzed retrospectively. Lower pole stones were relocated to the upper pole, where laser lithotripsy was performed. All patients were followed up in the clinic following the surgery and yearly thereafter. The stone-free status was assessed with a combination of an abdominal ultrasound and abdominal X-ray, or an abdominal non-contrast computed tomography if the stones were known to be radiolucent.

Results

A total of 480 consecutive patients who underwent RIRS for treatment of lower pole renal calculi, between January 2012 and December 2018, were analyzed from a prospectively maintained database of 3000 ureteroscopies. With a median follow-up time of 18.6 months, the mean SFR was 94.8%. The procedures were unsuccessful in 26 (5.4%) patients due to unreachable stones. The median stone size of the unreachable stones was 12 mm (range 10-30 mm). Multivariable logistic regression analysis revealed two predictors of SFR for lower pole stones: a small cumulative stone burden (odds ratio [OR]: 0.903, 95% confidence interval [CI]: 0.867-0.941, p<0.0001) and preoperative ureteral stent insertion (OR: 0.515, 95% CI: 0.318-0.835, p=0.007).

Conclusion

The long-term SFR of RIRS for the treatment of lower pole stones with basket displacement with appropriate patient selection is high.

Flexible Ureteroscopy and Nephroscopy for Stone Removal in Patients with Multiple Renal Calculi

Objective

Renal calculi are a common type of urological calculi and are associated with morbidity. This study was aimed at exploring the effect of flexible ureteroscopy and nephroscopy on stone removal in patients with multiple renal calculi.

Method

This randomized controlled trial included a total of 78 cases with multiple renal calculi in our hospital. The patients were randomly divided into the study and control groups and treated with flexible ureteroscopy and percutaneous nephrolithotomy with pneumatic ballistics, respectively. The surgery condition, levels of prostaglandin F2α (PGF2α), prostaglandin E2 (PGE2), keratocyte growth factor (KGF), renal function indices, and the incidence of complications were analyzed before and after surgery in the two groups.

Result

The operation time, the postoperative analgesia pump application time, one-time stone removal rate, the intraoperative blood loss, and hospital stay of the study group were significantly lower than those of the control group. Postsurgery, the levels of PGE2, PGF2α, and KGF in the study group were significantly lower than those in the control group. The serum levels of SCR, BUN, and NGAL in the study group were significantly lower than those in the control group. In addition, the incidence complications in the study group were significantly lower.

Conclusion

Flexible ureteroscopy and laser lithotripsy under nephroscopy were equally effective against multiple renal calculi. Flexible ureteroscopy reduced surgical trauma without affecting renal function and had a low incidence of complications.

Primary impact of simultaneous use of double devices through one-working channel when performing flexible ureteroscope with ureteral access sheath for single ureteral stone: In bench and retrospective clinical study

OBJECTIVES

This study aimed to compare the simultaneous use of two devices versus a single device through a single working channel in flexible ureteroscopy using a ureteral access sheath for single ureteral stones.

METHODS

In a bench study, the time to (i) set laser fiber, (ii) exchange laser fiber and nitinol basket through working channel, and (iii) pull out the device from working channel were measured 10 times in each step. In a clinical study, 156 patients who underwent flexible ureteroscopy with a ureteral access sheath for a ureteral stone in middle and upper ureter between April 2019 and November 2021 were assessed. One device was used at a time for 79 patients (S-Group) and two were simultaneously used for 77 (D-Group). Surgical outcomes and complications were compared.

RESULTS

In the bench study, the mean time to change from laser fiber to basket and from basket to laser fiber through the working channel were 26.1 ± 3.7 s and 23.6 ± 2.0 s (p = 0.084), respectively, which were significantly longer than the laser setup time (p < 0.001). In the clinical study, although the stone-free rate was not significantly different between the groups (S-Group 89.8%, D-Group 93.5%; p = 0.412), the median operation time was significantly shorter (p < 0.001) and the rate of postoperative stenting was significantly lower (p = 0.002) in the D-Group. There were no significant between-group differences in intra- and post-operative complications.

CONCLUSION

The simultaneous use of two devices through a single working channel is safe and could help save the time needed to exchange the laser fiber and nitinol basket.

Comparison of long-term results following ureteroscopic stone fragmentation with removal versus stone dusting without removal

Purpose:

To compare long-term results following ureteroscopic stone fragmentation and removal versus stone dusting.

Methods:

We conducted a retrospective analysis of patients who underwent ureteroscopy for renal calculi at two high-volume tertiary centres between 2012 and 2013, therefore allowing long-term follow-up. The surgeons differed in their technique, some performing dusting for the most part and the others fragmentation. Inclusion criteria were stone free at the first follow-up and the sole use of laser lithotripsy is either by dusting or by fragmentation. Operative and post-operative data as well as re-treatment rates were compared between the groups. Stone-free rates and long-term stone recurrence rates were analysed by a single radiologist blinded to the treatment technique.

Results:

Between 2012 and 2013, 669 ureteroscopies were performed at both centres. The study group included 100 patients, which met the inclusion criteria, equally distributed between dusting and fragmentation. The cumulative stone diameter in patients treated with dusting was significantly larger (12.7 mm versus 17 mm, p = 0.006). Operative time was shorter in patients treated with dusting (56 minutes versus 47.2 minutes, p = 0.6). The mean follow-up was 58.9 (standard deviation (SD) 17.2) and 69.4 (SD 13.8) months for the fragmentation and dusting-treated patients, respectively( p = 0.06). The long-term recurrence rate in the fragmentation group was 22% compared to 38% in the dusting group ( p = 0 .08). Most of the patients in the dusting group required a repeat ureteroscopy during their follow-up (28% versus 6%, p = 0.003). A multivariable logistic regression analysis revealed that the fragmentation was not associated with a lower stone recurrence rate when compared to dusting (OR 0.6, 95% CI 0.199-1.810, p = 0.3).

Conclusions:

The recurrence rate of renal stones was not significantly influenced by the choice of surgical techniques. However, dusting was associated with a greater need for repeat ureteroscopy than fragmentation with removal.

Level of evidence:

Not applicable

Comparison of Ultra-Mini Percutaneous Nephrolithotomy and Retrograde Intrarenal Surgery for Renal Stones: A Systematic Review and Meta-Analysis from the KSER Update Series

Miniaturized percutaneous nephrolithotomy (PCNL) and retrograde intrarenal surgery (RIRS) for renal stones have been developed to overcome the invasive disadvantages of PCNL. We aimed to compare the therapeutic effect and safety of ultra-mini percutaneous nephrolithotomy (UMPCNL) and RIRS for renal stones using an updated systematic review and meta-analysis. We searched clinical trials comparing UMPCNL and RIRS for renal stones using the PubMed, EMBASE, Cochrane Library, and Google Scholar databases up to October 2021. Seven studies were included in the current study. The renal stone size was 10–20 mm in three studies, 10–25 mm in one study, 10–35 mm in two studies, and not specified in one study. The stone-free rate of UMPCNL was higher than that of RIRS (p = 0.02; odds ratio (OR) = 2.01; 95% confidence interval (CI) = 1.12, 3.61). The complication rate showed no significant difference between UMPCNL and RIRS (p = 0.48; OR = 1.20; 95% CI = 0.73, 1.98). Regarding the operative time, UMPCNL was shorter than RIRS (p = 0.005; weighted mean difference (WMD) = −15.63; 95% CI = −26.60, −4.67). The hospital stay of UMPCNL was longer than that of RIRS (p = 0.0004; WMD = 1.48; 95% CI = 0.66, 2.31). UMPCNL showed higher efficacy than RIRS and similar safety to RIRS. UMPCNL may be a useful therapeutic option for moderate-sized renal stones.

Prospective, Randomized Comparison of Dual Lumen Versus Single Lumen Flexible Ureteroscopes in Proximal Ureteral and Renal Stone Management

INTRODUCTION

We sought to compare the safety, efficacy, efficiency and surgeon experience during upper urinary tract stone management with single-lumen versus dual-lumen flexible ureteroscopes.

MATERIALS AND METHODS

Seventy-nine patients with proximal ureteral or renal stone burden < 2 cm were randomized to a single-lumen or dual-lumen flexible ureteroscopy. We recorded times for ureteroscopy, laser lithotripsy, stone basketing, as well as intraoperative and postoperative complications. The rate of stone clearance and stone free status were calculated using computed tomography imaging. Surgeons completed a survey after each procedure rating various metrics regarding ureteroscope performance.

RESULTS

Thirty-five patients from the single-lumen group and forty-four patients from the dual-lumen group had comparable median ureteroscopy time (37 vs 35 minutes, p=0.984) and basketing time (12 vs 19 min; p=0.584). Median lithotripsy time was decreased in the dual-lumen group (single: 6 vs dual: 2 min, p=0.017). The stone clearance rate was superior in the dual-lumen group (single: 3.7 vs dual: 7.1 mm3/min, p=0.025). The absolute stone-free rate was superior for the dual-lumen group (single: 26% vs dual: 48%, p=0.045). No differences in intraoperative (single: 0% vs dual: 2%; p=0.375) and postoperative complications (single: 7% vs dual: 11%, p=0.474) were observed. Surgeons' ratings of the dual-lumen ureteroscope was superior for visibility, comfort, ease of use, and overall performance.

CONCLUSIONS

The use of the dual-lumen ureteroscope in patients with renal and proximal ureteral stones < 2 cm provided shorter lithotripsy time, higher stone clearance rates, improved stone free rate and superior surgeon ratings when compared to single-lumen flexible ureteroscopes.

Role of Multi-Detector Computed Tomography Indices in Predicting Extracorporeal Shockwave Lithotripsy Outcome in Patients With Nephrolithiasis

Background

Nephrolithiasis is one of the most common renal pathologies and is routinely encountered in daily practice. Non-contrast computed tomography (NCCT) is the gold standard diagnostic imaging modality for urolithiasis. The role of HU (Hounsfield units) in calculus as a predictor of extracorporeal shock wave lithotripsy (ESWL) has been studied in the past. This study aims to evaluate the role of HU value and various other NCCT indices in predicting the outcome of ESWL.

Material and methods

This was a prospective observational study that included 45 patients suffering from nephrolithiasis who underwent NCCT-KUB (kidney, ureter, and bladder) followed by ESWL. The NCCT indices were evaluated and correlated with the outcome of ESWL. NCCT-KUB was performed using multidetector SIEMENS® SOMATOM EMOTION 16-slice CT scanner (SIEMENS, Munich, Germany).

Results

In our study, the HU value turned out to be a statistically significant predictor of ESWL success (p <0.05), and the renal pelvis also proved to be a good prognostic indicator for ESWL success. The cut-off value of <1179 HU favored a successful outcome of ESWL, while if >1179 HU, ESWL is likely to fail. Hence, the successful outcome of ESWL is inversely proportional to the HU value. Renal pelvic calculi (n=14) showed a 100% success rate, which was better than all other calculus locations (p<0.05). However, the rest of the indices did not show any statistical significance.

Conclusion

Multi-detector NCCT-KUB indices can help in the selection of patients with a good prognosis for ESWL, which will prevent the patient from undergoing undesired invasive procedures.

Urolithiasis in Germany: Trends from the National DRG Database

INTRODUCTION

Urolithiasis is a common disease leading to a high socioeconomic burden due to treatment costs and sickness leave. The aim of this study was to evaluate recent trends in the incidence of urolithiasis in Germany and in the use of therapeutic interventions.

METHODS

Treatment data for all in-patient hospital episodes for urolithiasis between 2005 and 2016 were extracted from the national DRG statistics at DESTATIS and analysed with regard to the corresponding procedures according to the OPS code.

RESULTS

Incidence for urolithiasis was stable at around 120,000 cases per year during the observation period with a male:female ratio of 2:1. Rising numbers were noted for patients >80 years. Nevertheless, the number of coded procedures rose significantly with a marked disproportionate transition from extracorporeal shock wave lithotripsy towards ureterorenoscopy. Percutaneous nephrolithotomy was performed more frequently on a smaller scale.

DISCUSSION/CONCLUSION

While the global incidence of urolithiasis is still rising, Germany, as other Western countries, has reached a plateau. There is a remarkable trend towards invasive treatment of even asymptomatic kidney stones. Besides the effects on individual patients with increased risk for complications, this results in a higher monetary burden to the health care system and society.

Ex-vivo Renal Stone Dusting: Impact of Laser Modality, Ureteral Access Sheath, and Suction on Total Stone Clearance

INTRODUCTION AND OBJECTIVES

Conventional renal stone dusting is challenging; the holmium laser (Ho:YAG) and holmium with MOSES Effect (Ho:YAG-MOSES) fail to uniformly produce fragments <100 microns (i.e. dust). The superpulse thulium fiber laser (sTFL) may more effectively render uroliths into "dust," and may thus improve stone free rates. Accordingly, we performed ex-vivo evaluations with all three laser modalities, assessing stone fragments and stone clearance.

METHODS

Seventy-two ex-vivo porcine kidney-ureter models were divided into 12 groups of six: laser type (Ho:YAG, Ho:YAG-MOSES, sTFL), ureteroscope (URS) with and without applied suction, and presence or absence of a 14Fr ureteral access sheath (UAS). Calcium oxalate stones were pre-weighed and implanted into each kidney via a pyelotomy. Stones were treated at 16 watts using dusting settings of 0.4Jx40Hz (Ho:YAG) 0.2Jx80Hz (Ho:YAG-MOSES), and 0.2Jx80Hz (sTFL) for up to 20 minutes. No stone basketing was performed. Kidneys were bi-valved and residual fragments were collected, dried, weighed, and sieved to determine fragment size and stone clearance.

RESULTS

Initial stone mass (mg), procedure time (sec), and laser energy expenditure (kJ) were similar in all 12 groups. The greatest stone clearance was seen with sTFL+suction+UAS (94%) compared to a conventional technique (Ho:YAG+no suction+no UAS) (65%, p<0.01). The use of sTFL provided greater stone clearance than Ho:YAG or Ho:YAG-MOSES. Aspiration improved stone clearance for sTFL (p=0.01) but not for Ho:YAG or Ho:YAG-MOSES, consistent with the creation of smaller fragments with sTFL. Presence of a 14F UAS improved stone clearance in all scenarios (p<0.01).

CONCLUSIONS

In this ex-vivo study, stone clearance was optimized under the following conditions: sTFL laser, 14F ureteral access sheath, and aspiration. This combination resulted in 94% of stone fragments cleared; the 6% remaining fragments were all <2 mm. In all scenarios, deployment of a 14Fr UAS improved stone clearance.

Flexible Ureteroscopy for Treatment of Upper Urinary Tract Calculus

The aim of this article is to illustrate a step-by-step guide to flexible ureteroscopy (URS) for treatment of upper urinary tract calculus. Preoperative evaluation of the patient with focus on comorbidities is paramount for the type of stone procedure to be performed. In this article, the steps of operating room setup, patient positioning, gaining access to the upper urinary tract, flexible URS, laser lithotripsy, basket extraction of stone fragments, and placement of a ureteral stent are described. The importance of clearance of the ureter before flexible URS in the case of pre-existing ureteral stone is also described.

Silodosin for Prevention of Ureteral Injuries Resulting from Insertion of a Ureteral Access Sheath: A Randomized Controlled Trial

BACKGROUND

The ureteral access sheath (UAS) is an ancillary device widely used by urologists, but acute ureter injury may occur following its insertion. Preoperative selective oral α1-blockers can reduce intraureteral pressure, and prevent ureteral wall injury during UAS insertion.

OBJECTIVE

To compare perioperative data of patients who underwent flexible ureterorenoscopy (fURS) with UAS with and without premedication with silodosin.

DESIGN, SETTING, AND PARTICIPANTS

Single-blind, 100 patients from a single institution who underwent retrograde intrarenal surgery for kidney and upper ureter stone removal were prospectively allocated from May 2018 to March 2019.

INTERVENTION

The experimental groups received silodosin for 3 d preoperatively.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary endpoint included ureteral injuries after UAS insertion that were assessed according to endoscopic classification. The secondary endpoint was an evaluation of whether premedication with silodosin had any effect on postoperative outcomes.

RESULTS AND LIMITATIONS

A total of 44 and 43 patients were randomly assigned to the control and experimental groups, respectively. Silodosin prevented significant postoperative ureteral injury involving the smooth muscle layer more successfully than in the control group (9.3% vs 27.3%; p = 0.031). There was no significant difference in the overall complication rate as determined by the modified Clavien-Dindo classification system and the computed tomography scan stone-free rate postoperatively. Patients who received silodosin before fURS reported lower pain scores than those in the control group using a visual analog scale (p = 0.009). Limitation included a lack of placebo comparison.

CONCLUSIONS

Our data suggest that preoperative silodosin protects against significant ureteral injury related to UAS insertion during fURS and decreases postoperative pain level. Silodosin premedication might be an effective and safe technique to replace prestenting.

PATIENT SUMMARY

We investigated the preventive effect of an α-blocker against perioperative complication caused by ureteral access sheath inserted during flexible ureterorenoscopy. Taking silodosin before surgery prevented ureter wall injury during surgery and immediately improved postoperative pain.

Predictors of Repeat Surgery and Stone-related Events After Flexible Ureteroscopy for Renal Stones

OBJECTIVES

To evaluate the risk of repeat surgery and stone-related events after flexible ureteroscopy (fURS) for renal stones, and to identify their predictive factors.

PATIENTS AND METHODS

This was a single-center, retrospective cohort study of patients (n = 664) who underwent fURS for renal stones with or without concomitant ureteral stones between January 2012 and December 2019. The primary outcomes were time to ipsilateral stone-related surgical intervention and any stone-related event (including ipsilateral renal colic, symptomatic ureteral calculi, obstructive urinary tract infection, and surgical intervention).

RESULTS

During median follow-up of 31.1 months, 103 (15.5%) and 135 (20.3%) patients experienced surgical intervention and any stone-related event, respectively. The estimated 2-year intervention-free survival and stone-event-free survival was 86.9% and 81.6%, respectively. On Cox multivariate analysis, younger age (hazard ratio [HR] 0.96), history of stone surgery (HR 2.17), larger preoperative stone burden (HR 1.03), and larger residual fragment (HR 1.09) showed an association with future intervention. Use of the four identified risk factors (age ≤60, history of stone surgery, stone burden ≥20 mm, and residual fragment ≥4 mm) allowed stratification of patients based on the risk of future intervention (low [score: 0-1], intermediate [2], and high [3-4] risk). The estimated 2-year intervention-free survival rates in low-, intermediate-, and high-risk groups were 96.2%, 86.4%, and 71.3%, respectively.

CONCLUSION

Patients undergoing fURS are at risk of future ipsilateral surgical intervention and stone-related events. Our simple predictive tool can facilitate treatment decision-making by identifying patients who are at high risk of recurrence.

Residual Stone Fragments After Percutaneous Nephrolithotomy: Shockwave Lithotripsy vs Retrograde Intrarenal Surgery

Background: Despite technology incorporation to percutaneous nephrolithotomy (PCNL), residual stone fragments (RSFs) may still persist after PCNL and need to be addressed to avoid regrowth or ureteral obstruction. The objective of this study was to compare the outcomes of retrograde intrarenal surgery (RIRS) to extracorporeal shockwave lithotripsy (SWL) for treating patients with RSFs after a previous standard PCNL. Materials and Methods: Adult patients with RSF after a standard PCNL submitted to RIRS or SWL in our Institution from January 2017 to January 2020 were retrospectively studied. Stone-free rate (SFR) was evaluated on postoperative day (POD) 90 by noncontrast CT (NCCT) or ultrasound and kidney, ureter, and bladder radiograph (KUB) for each renal unit. Surgical complications based on Clavien-Dindo classification during the 90 days of follow-up were recorded. Sample size was calculated for a power of 80% and a significance level of 0.05, assuming SFR of 20% for SWL and 50% for RIRS. Results: Thirty-three patients treated by SWL were compared with 36 patients treated by RIRS. Hospitalization time was longer in the RIRS group (4.18 vs 12.33 hours, p = 0.001). SFR and success rate were lower in SWL than RIRS group (24.2% vs 58.3%, p = 0.007 and 30.3% vs 72.2%, p = 0.004, respectively), using POD 90 NCCT in 81.8% and ultrasound and KUB in 18.2% of the SWL group and using POD 90 NCCT in 100% of the RIRS group. Minor complications (Clavien-Dindo < III) occurred in 11 of 36 (30.6%) patients submitted to RIRS and in 2 of 33 (6.1%) patients submitted to SWL group (p = 0.025). Two patients (6.1%) of the SWL group had Clavien-Dindo IIIb complication owing to Steinstrasse and were submitted to ureteroscopy. Emergency room visits were similar between groups (6.1% vs 8.3%, p = 1.0). Conclusions: RIRS has better SFR, higher minor complications, and lower major complications than SWL for the treatment of RSFs after standard PCNL.

In-vitro and in-vivo new evidence for Flexor® Vue™ deflecting endoscopic system use: optimization of the stone free rate (SFR) after flexible ureteroscopy and Ho:YAG laser lithotripsy

To test in-vitro and in-vivo the Flexor® Vue™ deflecting endoscopic system (FVDES) as a new technology able to improve the removal of residual intrarenal fragments.This is an observational prospective "proof of concept" study performed in patients with renal calculi treated with flexible ureteroscopy and Ho:YAG laser lithotripsy (f-URS) in Humanitas Research Hospital (Rozzano, Italy). We assessed feasibility, efficacy and safety of FVDES as an in-vivo tool for removing residual fragments after f-URS. The stone-free rate (SFR) at 30 days post-operatively was evaluated using CT. An in-vitro model was developed to evaluate the FVDES when used for this purpose.Eleven patients (M/F ratio: 7/4, mean age 63.5 ± 8.3) were treated. The stones were located in the lower calyces and the renal pelvis in 3 and 8 patients, respectively. Mean stone size was 18 ± 3.2 mm. The procedure with FVDES was feasible and effective in all the patients. Mean operative time was 82 ± 13.7 min and median hospitalization was of 1.5 days. The SFR after 90 days was 81% (9/11). We reported no relevant complications (Clavien-Dindo > 2); one patient had fever and was treated with antibiotics. The experimental in-vitro model demonstrated the efficacy of FVDES, allowing the removal of about 90% of fragments.Our study showed that FVDES is effective when used as a tool for retrieval of residual fragments at the end of f-URS. This technology could ensure a complete cleaning of the intrarenal collecting system and represent a safe alternative to basketing.

Treatment of isolated small renal stones leads to resolution of symptoms and should be routinely offered to patients: retrospective outcomes from a university hospital

INTRODUCTION

Treatment of smaller renal stones and the symptomatic value it offers to patients is often debated. We wanted to analyse surgical outcomes for treatment of small renal stones and whether treatment resulted in symptom resolution.

MATERIALS AND METHODS

All patients who underwent ureterorenoscopy (URS) for isolated symptomatic small renal stones ≤10 mm over a 7-year period were retrospectively included and subdivided into those with stones of ≤7 mm (Group A) and stones of 8-10 mm (Group B). Patients with multiple renal stones, ureteric stones, or combined renal and ureteric stones were excluded. Based on the symptoms, the patient groups were those with pain, urinary tract infection (UTI) and haematuria. Resolution of symptoms was defined as no symptoms during the follow-up period.

RESULTS

A total of 109 patients with a single small renal stone ≤10 mm underwent URS and stone treatment, with mean age of 50 years and a male:female ratio of 1:1.2. The mean operative time was significantly longer in Group B (55.9 min vs 33.07 min, p = 0.001). In total, 97.2% (n = 70) of patients in Group A and 83.7% (n = 31) of patients in Group B were stone free (p = 0.017). Complete resolution of symptoms was seen in 63 (92.6%), 24 (85.7%) and 13 (100%) patients with pain, UTI and haematuria, respectively. There were no statistically significant differences in symptom resolution between patients with stones ≤7 mm and those with stones 8-10 mm in size.

CONCLUSION

Ureteroscopic treatment is a feasible option for small symptomatic stones, since it may lead to symptom resolution. Based on our study we would recommend that patients with symptomatic small renal stones are offered endoscopic treatment.

Analysis of performance factors in 240 consecutive cases of robot-assisted flexible ureteroscopic stone treatment

Flexible ureteroscopy is the keystone of modern kidney stone treatment. Although a simple surgical technique achieves good clinical results and a low complication rate, there are high demands on the surgeon's dexterity and ergonomic restrictions. Robotic-assisted flexible ureteroscopy (rfURS) could overcome these limitations. After 4 years of use of rfURS at a tertiary stone center, performance factors were analyzed to define the role of rfURS in kidney stone management. A rfURS system was installed in August 2014 at the SLK Kliniken (Heilbronn, Germany). Treatment data of N = 240 consecutive patients undergoing rfURS were prospectively collected and analyzed. The patient cohort represents typical stone formers. N = 240 renal units containing 443 stones with an average stone load of 1798 mm³ were treated. Surgical parameters as well as the peri- and postoperative complications were recorded, analyzed and compared to the current data in the literature. OR time 91 min, stone treatment time 55 min, stone treatment efficacy 33 mm³/min; perioperative complications 5.4%; robot times: preparation 5 min, docking 5 min, console time to stone contact 6 min, console time 75 min; postoperative complications 6.7%; postoperative length of stay 1.5 days; stone-free rate (residuals < 2 mm) 90% and re-treatment rate 8.75%. This consecutive series represents real-life data about the utilization of rfURS. The detailed analysis of performance factors revealed the successful utilization of the first generation of robotic systems in endourologic stone surgery, and indicates that the robot performs comparably to conventional flexible URS. Optimal ergonomics maintain the surgeon's endurance in long-lasting surgeries.

Stone residual fragments: A thorny problem

Urolithiasis represents a widespread and common disorder among the world population, with a predicted increase in affected patients in the coming years. Treatment of renal and ureteral stones varies widely, and achieving true stone-free status in all patients is still difficult. Moreover, imaging used to assess residual fragments following procedure impacts the diagnosed stone-free rate percentage considerably. In particular, the use of computed tomography scans has led to a better evaluation of residual fragments as well as so-called clinically insignificant residual fragments, which in a considerable number of cases are, despite their definition, causes of adverse urological events, thus creating a thorny problem for both patients and urologists. Currently, there is no gold standard or validated protocol regarding the management, clearance and prevention of residual fragments. In this article, we review the current literature regarding residual fragments, clinically insignificant residual fragments and their natural history, reporting on diagnostic methods, incidence, complications and outcome with the use of less invasive procedures, taking into consideration viable treatment and management of patients affected.

A Retrospective Study of Kidney Stone Recurrence in Adults

Background

Nephrolithiasis or kidney stone disease (KSD) is a common disorder worldwide. Despite the availability of a variety of effective management strategies, KSD recurrence remains a problem. In the present study, we investigated the KSD recurrence after the treatment of the first stone episode.

Methods

Medical records of all patients who had KDS treated in our department from January 2012 to January 2016 were retrospectively reviewed. A total of 146 patients who had KDS recurrence were identified. The demographic information, biochemical data, treatment methods, report of hydronephrosis severity and stone chemical compositions were collected and analyzed.

Results

We reported that: 1) Sixty four (43.8%) out of 146 patients with stone recurrence were overweight or obese; 2) Of all 146 patients with stone recurrence, 86 (58.9%) had hyperlipidemia, 77 (52.4%) had hyperuricemia and 64 (43.8%) had hyperglycemia; 3) Mini-invasive methods were mostly used for the treatment of the first stone episode; 4) The most chief complaint differed during the first episode and recurrence; 5) The number of patients who had grades 3 and 4 hydronephrosis was significantly lower during recurrence compared with that in the first stone episode; 6) Seventy nine (54.1%) patients with recurrence had stone of calcium oxalate.

Conclusions

Majority of patients with KSD recurrence have overweight/obesity, hyperlipidemia, hyperuricemia and hyperglycemia, indicating a role of metabolic disorders in stone recurrence. Mini-invasive methods are the mainstay for the management of the first stone episode. The degree of hydronephrosis is significantly reduced during stone recurrence, possibly due to increased awareness of the disease and thereafter the change of lifestyle in patients. Over half of recurrent stones are of calcium oxalate.